1. Field of the Invention
The present invention relates to a method of diffusing an impurity-diffusing component and a method of manufacturing a solar cell.
2. Description of the Related Art
In semiconductor manufacturing fields, particularly in solar cell manufacturing fields, aiming at an improvement in manufacturing throughput, there has been recently a need for a technique of simultaneously diffusing a P-type impurity-diffusing component containing boron and an N-type impurity-diffusing component containing phosphorus in a semiconductor substrate to selectively form a P-type impurity diffusion layer and an N-type impurity diffusion layer on the semiconductor substrate. In the conventional method of manufacturing a semiconductor substrate having P-type and N-type impurity diffusion layers, an impurity diffusion layer has been formed by using phosphoryl chloride (POCl3) and boron tribromide (BBr3) as impurity-diffusing components and separately subjecting the components to gaseous diffusion. It has been impossible to selectively and simultaneously diffuse boron and phosphorus in a semiconductor substrate by such gaseous diffusion.
On the other hand, for example, Japanese Patent Application Laid-Open (JP-A) No. 2012-114452 discloses a technique of selectively printing a coating liquid of a p-type dopant source and a coating liquid of an N-type dopant source on a substrate by an ink jet printing method or a screen printing method to form each conductivity type of dispersing agent pattern, and diffusing impurity-diffusing components from each of the dispersing agent patterns to selectively form each conductivity type of impurity diffusion layer.